The invention relates to a process for treating wastes from the machining of ferromagnetic materials, and to an apparatus for carrying out such a process.
German Published Patent Application No. DE 37 39 496 discloses a band filter system for purifying a contaminated liquid, especially machining coolant which is used in the cutting of metals. A band filter system of this kind is provided with a dirt chamber to which the coolant is fed. Underneath this dirt chamber is a filter support on which a non-woven filter is situated. The non-woven filter is progressively moved automatically in steps according to the amount of waste deposited on it. The wastes are removed from the system by the non-woven filter and passed into an accumulator. This waste contains, in addition to a great amount of metal chips and metal dust, grinding residues, such as corundum, for example. Moreover these wastes are still heavily loaded with oil and with emulsion.
The disposal of this mixture without further treatment can be performed only by licensed waste disposal companies, and only at special dumps. Attempts have, of course, been made to feed this mixture into an incinerator. Because of the metal and corundum components, however, this is an uneconomical solution. Due to the high content of foreign substances, it is also impractical to melt down the metals in a smelting furnace.
German Published Patent Application No. DE 37 25 528 discloses an apparatus for compressing and removing water from suspensions, sludges or the like. It has been found, however, that it is impossible to remove the oil adhering to such residues, even under high pressures.